BALI, Indonesia — Indonesian prosecutors on Tuesday sought jail sentences of 18 years for an American man and 15 years for his girlfriend if they are found guilty of murdering the woman's mother while vacationing on the resort island of Bali last year.

The prosecutors told the court that Tommy Schaefer and Heather Mack, who appeared in court with their 2-week-old daughter, were guilty of premeditated murder. The panel of judges could ignore the sentencing request and decide to impose the maximum, death by a firing squad, if it convicts them.

"The defendant has committed sadistic acts to her own mother," chief prosecutor Eddy Arta Wijaya told the court at Mack's trial. "However, we've decided to be lenient because she repeatedly expressed remorse and has a newborn baby."

The badly beaten body of Sheila von Wiese-Mack, 62, was found in a suitcase in the trunk of a taxi outside an upscale hotel in August.

Wijaya asked the judges to declare the defendants guilty with the fact that Schaefer deliberately brought a metal fruit bowl when he came to the room at the St. Regis where Mack and her mother were staying, on a different floor from his own room.

Mack helped stuff her mother's body in the suitcase by sitting on it to enable Schaefer to close it, prosecutors said.

Schaefer, 21, and Mack, 19, both from Chicago, are being tried separately at the Denpasar District Court on Bali. The judges and prosecutors are the same in both trials.

The defendants sat quietly with Schaefer on the verge of tears as the sentence request was read. The defendants and their lawyers will respond to the prosecution's case next week, and verdicts are expected in late April.

Schaefer has testified that von Wiese-Mack was angry at him when she learned about her daughter's pregnancy. He said at previous court hearings that she insulted him and Mack, wanted her to get an abortion and strangled him in a heated argument before he struck her several times with the fruit bowl.

At Tuesday's hearing, another prosecutor, Ni Luh Oka Ariani Adikarini, said testimony and evidence showed that Schaefer deliberately planned to kill the victim.

"There is no excuse for the deeds of the defendant," Adikarini said and recommended the court to sentence Schaefer to 18 years in jail.

The prosecutors did not explain why they sought less than the maximum penalty for him.

The court had delayed the hearing last week because the couple's baby, Stella, became sick in prison, but doctors said the baby has recovered from jaundice.